Workmen{3 s cage for excavation work

ABSTRACT

A workmen&#39;&#39;s cage adapted to be positioned within a trench or the like to protect workmen in the case of a cave-in has a top wall and side walls of reinforced screen material with one of the side walls hingedly connected to the top wall for swinging movement toward the opposite side wall to facilitate removal of the cage from a trench or the like after a cave-in. An over-center hinge interconnects the side walls to brace the side walls in the normal use condition of the cage and can be selectively released from a location above the cage by a pull-cable to allow the pivotal side wall to be swung inwardly after a cave-in, enabling easy lifting removal of the cage.

United States Patent 119] Benning Dec. 2, 1975 1 1 WORKMENS CAGE FOR EXCAVATION [21] Applv No.: 486,692

38,378 1954 Poland 61/41 A Primary ExaminerPaul R. Gilliam Assistant ExaminerV. N. Sakran Attorney, Agent, or FirmBurton, Crandell & Polumbus [57] ABSTRACT A workmen's cage adapted to be positioned within a trench or the like to protect workmen in the case of a cave-in has a top wall and side walls of reinforced screen material with one of the side walls hingedly connected to the top wall for swinging movement toward the opposite side wall to facilitate removal of the cage from a trench or the like after a cave-in. An over-center hinge interconnects the side walls to brace the side walls in the normal use condition of the cage and can be selectively released from a location above the cage by a pull-cable to allow the pivotal side wall to be swung inwardly after a cave-in, enabling easy lifting removal of the cage.

11 Claims, 7 Drawing Figures PEltEl'lt Dec. 2, 1975 Sheet 1 of 2 v s rig-ii! US. Patent Dec. 2, 19.75

Sheet 2 of 2 WORKMENS CAGE FOR EXCAVATION WORK BACKGROUND OF THE INVENTION Excavation work, particularly that carried out by hand and in narrow trench-like areas, has traditionally been very dangerous work in that the side walls of the trench may cave-in thereby covering the workers in possibly a fatal accident. To avoid these accidents, numerous laws have been passed requiring the side walls of such trenches to be inclined outwardly at a specific angle so that they cannot collapse causing harm to the workers in the trench. Wall shoring devices have also been developed to retain the side walls of the trench while workmen are working therein to prevent such a cave-in. These devices typically have rigid brace members bridging the trench to maintain a predetermined spacing between side walls of the device which define a work area therebetween. Of course, such devices are difficult to disassemble and reassemble at various locations along the trench site. Other devices have been developed which are removable from the trench but in the event of a cave-in they are extremely difficult to re move since the pressure of the collapsed side walls of the trench against the device establishes an almost insurmountable friction grip on the device.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a new and improved workmens cage for excavation work which reliably protects workmen from cave-ins and is easily removable from a trench after a cave-in.

It is another object of the present invention to provide a new and improved workmens cage for excavation work wherein one side wall of the cage is selectively movable toward the opposite side wall to release the cage from pressure exerted thereon after a cave-in of a trench so that the cage can be easily lifted from the trench.

It is another object of the present invention to provide a workmen s cage for excavation work wherein the cage includes two parallel side walls defining a space therebetween in which workmen can work and wherein one of the side walls is selectively pivotal inwardly toward the opposite side wall through operation of a release system which is operable from a remote location above the cage.

It is another object of the present invention to provide a workmens cage for excavation work which can be readily removed from a caved-in site with the workmen in the cage so that the workmen are removed with the cage in a safe and a reliable manner.

SUMMARY OF THE INVENTION The present invention relates generally to safety equipment for laborers and more particularly to a cage which defines a safe work area in which workmen can carry on excavation work.

The workmens cage of the present invention has been designed to provide a safe work area for excavation workers and to facilitate easy and safe rescue of the workers in the event of a cave-in. More particularly, the workmens cage of the present invention includes a pair of side wall members connected to opposite side edges of a top wall member with one of the side walls pivotally connected to the top wall for swinging movement toward the opposite side wall. The side walls are normally retained in parallel spaced relationship by a collapsible brace which can be released to allow the pivotal side wall to swing inwardly toward the opposite side wall when desired. In the event of a cavein at the excavation site, the top and side walls prevent the caved-in material from entering the cage in any substantial quantities and the pressure exerted upon the side walls by the caved-in material, which would normally prevent the cage from being easily removed from the excavation site, can be relieved by releasing the collapsible brace and allowing the pivotal side wall to swing inwardly so that the cage can be pulled from the excavation site by an overhead crane or the like. The cage further includes an access door through the top wall so that workmen can enter and leave the cage during work shifts and also escape from the cage after a cave-in if they do not wish to remain in the cage while it is lifted from the caved-in excavation site.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the workmens cage of the present invention with parts removed for clarity.

FIG. 2 is an end elevation of the workmens cage of FIG. 1 positioned within an excavation site.

FIG. 3 is an end elevation similar to FIG. 2 with the pivotal side wall in a folded position.

FIG. 4 is an enlarged fragmentary vertical section illustrating the pull cable system for releasing the bracing members.

FIG. 5 is an enlarged fragmentary perspective view with parts removed at one end of the workmens cage of FIG. 1.

FIG. 6 is an enlarged fragmentary perspective view similar to FIG. 5 with the pivotal side wall in its folded position.

FIG. 7 is an enlarged vertical section taken through one of the over-center bracing members.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, the workmens cage 10 of the present invention can be seen to include a top wall 12, a fixed side wall 14, a pivotal side wall 16, end walls 18, and a pair of bracing members 20 interconnecting the side walls 14 and 16 at opposite ends thereof.

The top wall 12 is of generally rectangular configuration and has a peripheral framework 22 of high strength steel or the like with lateral and longitudinal frame members 24 and 26 respectively defining a horizontal gridwork within the peripheral framework 22. The top wall is covered with a wire mesh screen 28 to prevent the ingress of most dirt materials. An opening 30 is provided through the top wall for access to the interior of the cage and a removable door 32 with a handle 34 on the top surface thereof is sized to close the access opening or passage 30 when the cage is in use.

The side walls 14 and 16 each have a peripheral framework 36 with horizontal and vertical inner frame members 38 and 40 respectively forming a gridwork of reinforcement for a wire mesh screen 42 which covers the gridwork on each of the side walls. The pivotal side wall 16 is hinged to one edge of the top wall l2'by a plurality of longitudinally spaced hinge members 44 which allow the pivotal side wall to swing inwardly into downwardly convergent relationship with the fixed side wall 14.

Each end wall 18 depends from an end of the top wall 12 and is connected to the fixed side wall 14 so as to extend approximately one half of theheight of the side wall and partially close the space between the side walls at opposite ends of the cage. Each end wall has a pcripheral frame member 46 extending in an arcuate manner from the top wall 12 adjacent its connection to the pivotal wall 16 to a location on the fixed side wall 14 approximately midway along its vertical extent. A straight frame member 48 also extends from the top wall to the fixed side wall to form a diagonal frame member for each of the end walls. Each end wall is covered with a wire mesh screen 50, similarily to the side and top walls, to prevent the ingress of substantial quantities of dirt material into the cage.

The bracing members 20, in the preferred form, are over-center hinges including two hinge arms 52 and 54 with the hinge arms having their outer ends pivotally connected to the peripheral frames of the opposite side walls and their inner ends pivotally connected together. One hinge arm 52 is slightly longer than the other hinge arm 54 so that it extends beyond the pivotal connection of the arms. The shorter hinge arm 54 consists of a pair of spaced parallel bars 56 which are bridged at an intermediate location by an abutment block 58. The abutment block is positioned so as to engage the extension portion 60 of the longer hinge arm 52 when the hinge is passed beyond center in a downward direction so that the abutment block limits downward pivotal movement of the hinge. In the over-center position, with the longer arm 52 engaging the abutment block 58, the hinge serves as a rigid brace holding the side walls of the cage in substantially parallel relationship.

A connector 60 is anchored to each hinge bracing member at the connection of the hinge arms and serves as a connection point for a longitudinally inextensible link chain 62 which hangs from one corner 64a of a pivot bracket 64 mounted at the end of the top wall 12 for pivotal movement about a horizontal axis. The link chain 62 has a quick release hook-type coupling 66 on its lower end which can be extended through the closed loop connector 60 to secure the chain to the associated hinge 20. It will be apparent that an upward pulling force on the chain will pull the center portion of the associated hinge upwardly so that once it has passed the centered position, wherein the arm members 52 and 54 are in longitudinal alignment, the pivotal side wall 16 will be free to pivot inwardly toward the fixed side wall 14.

The opposite corner 64b of the pivot bracket 64 is connected to a longitudinally inextensible. cable 68 which extends upwardly and inwardly toward an eyelet 70 wherein it is joined with a like cable 68 which is connected to the pivotal elbow bracket 64 at the opposite end of the top wall. At the eyelet 70, the two upwardly and inwardly inclined cables 68 are merged to define a looped cable 72 which can be grasped by an overhead crane or the like to transport the cage into and out of an excavation site. It will be appreciated that a pulling force on the upwardly convergent cable sections 68 of the looped cable 72 will place a pivotal force on the elbow brackets 64 causing the brackets to pull the chains 62 at opposite ends of the cage to apply an upward pulling force on the hinges 20 to release the hinges thereby allowing the pivotal side wall 16 of the cage to be swung inwardly as viewed in FIG. 3. Of course, to reposition the pivotal side wall into its parallel relationship with the fixed side wall 14, the overcenter hinges 20 are pivoted downwardly until they pass center with the extension portion 60 of the longer hinge arm 52 engaging the abutment block 58 and thereby bracing the side wall members in rigid parallel spaced relationship.

To facilitate entry and exit from the cage, a ladder 74 is mounted upon the inner surface of the fixed side wall A 14 of the cage in alignment with the access passage so that workmen can get from the lower end of the cage at the bottom of the excavation work site to the access door 32 merely by climbing the ladder. Further, the ladder can serve as a location where workmen within the cage can grab onto the cage when it is removed from an excavation site where a cave-in has prevented the workers from escaping through the door passage.

At opposite ends of the lower horizontal peripheral frame members 38a of each side wall, the frame members 36a are bevelled so that each lower frame member 38a serves as a skid-for sliding the cage along the excavation site. Cable attachment brackets 76 are provided on the frame members so that a pull cable 78 can be affixed thereto to allow the cage to be pulled with power driven means adjacent the excavation site to advance the cage to new locations along the excavation site.

In operation, the cage is first placed in its use condition by extending the over-center hinges 20 into the bracing condition so that the side walls 14 and 16 are held in parallel spaced relationship. The quick release coupling hooks 66 on the lower ends of the chain members 62 are released from the hinges 20 so that the hinges are not accidentally released while the cage is being lowered into an excavation site. To positively lock the hinges in the bracing condition, a pair of raised brackets 80, having axially aligned apertures 82 therethrough, are secured on opposite sides of each of the shorter hinge arms 54 near the pivotal connection to the longer hinge arms52 so that lock pins 84 can be extended through the aperatures 82 in overlying relationship with the inner ends of the hinge arms 52 to assist in preventing pivotal movement of the hinge arms. For convenience, the lock pins 84 may besuspended by flexible chains 86 from side wall 16 and channeled supporting brackets 88 may be mounted along the side of each hinge arm 54 to support the pins and help retain them in the apertures 82.

After the hinges have been secured in the bracing condition, a crane can then lower the cage, by connection to the cable loop 72 across the top of the cage, into the excavation site until the skid members 36a at the lower end of each side wall engage the bottom of the excavation site. With the cage in this position, workmen can enter the cage through the access passage 30 by removing the access door 32 and climbing down the ladder to the lower end of the cage. The workmen can then connect the quick release hook couplings 66 to the hinges 20 and begin their work within the cage. When they have finished working in a given area, the cage can be advanced along the excavation site by pulling the pull cable 78 at one end of the cage to slide the cage along the bottom of the excavation site until it is in the newly selected position.

in the event there is a cave-in, the majority of the caved-in material will be prevented from entering the cage by the screen covering which establishes a hollow cavity in the cage within which the workmen can remain. The cavitty is relatively large and, therefore, adequate air is available to the workmen during rescue operations-If the caved-in material does not cover the top with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.

of the cage, the workmen can safely climb the ladder, remove the access door 32, and climb out of the cage to safety. However, if the caved-in material does not cover the top of the cage an overhead lift mechanism, such as a crane, can grasp the looped cable 72 across 5 the top of the cage and apply a pulling force thereto to pull the over-center hinges upwardly allowing them to release and pivot the pivotal sidewall 16 inwardly toward the fixed side wall 14 thereby relieving the pressure of the caved-in material against the side wall. This also reduces the width of the cage along its bottom end so that it can be freely pulled from the caved-in material. The workmen can cling to the ladder or to any of the other frame members of the cage as the cage is pulled from the caved-in material and thereby be freed from the caved-in material along with the cage.

It should be noted that the pivotal elbow brackets 64 limit the distance which the chains 62 are allowed to be pulled by the looped cable 72 so that the chains do not continue pulling the hinges 20 upwardly with continued pulling of the looped cable as this will cause maximum pivotal movement of the side wall 16. While maximum pivotal movement of the side wall 16 is not necessarily bad, it does limit the remaining space available for the workmen inside. lt will, therefore, be appreciated that a pulling force on the looped cable 72 will pull the chains 62 a distance which is just sufficient to release the hinges by pulling them beyond the centered positions. With the hinges so released, pressure applied against the pivotal side wall 16 can swing the pivotal side wall to its maximum folded positions, if this becomes necessary for removal of the cage from the caved-in material, but if the pressure applied to the pivotal side wall 16 by the caved-in material is not excessive, the pivotal side wall will not be swung to its maximum folded position and the cage can be removed from the caved-in material with the pivotal side wall in the condition illustrated in FIG. 3.

Although the present invention has been described What is claimed is:

l. A workmens cage for excavation work comprising combination:

a top wall,

a pair of side walls depending from opposite side edges of the top wall,

pivot means connecting the top portion of one of said side walls to the top wall for pivotal movement of said one side wall selectively between a first position spaced from the other side wall and a second position wherein said one wall, below said pivot means, is pivoted inward convergent to said other wall,

means fixing the angular relationship of said other side wall to the top wall,

brace means extending between and interconnecting the side walls in downwardly spaced relation to said top wall, said brace means being selectively movable between an extended condition maintaining said one wall in the first position thereof and a collapsed condition whereby the brace means allows pivotal movement of said one side wall relative to the top wall, and

release means connected to said brace means and operable from above said top wall for releasing said brace means from said extended condition and allowing pivotal movement of the lower portion of the one side wall toward the other while a fixed spacing is retained between the top edges of the side walls.

2. The workmens cage of claim 1 wherein said one side wall is substantially perpendicular to the top wall when said brace means is in the bracing condition and is downwardly convergent toward the other side wall when the brace means is in the collapsed condition.

3. The workmens cage of claim 2 wherein said brace means consists of an over-center hinge which is released to its collapsed condition by a upwardly directed force.

4. The workmens cage of claim 3 wherein said release means includes longitudinally inextensible means which can be pulled from a location above the cage to apply an upward pulling force to the over-center hinge to release the hinge to its collapsed condition.

5. The workmens cage of claim 4 wherein said release means includes a pivotal arm mounted on the cage adjacent the top wall, said pivotal arm being connected by first longitudinally inextensible means to the over-center hinge and having second longitudinally inextensible means accessible from above the cage for releasing the hinge to its collapsed condition.

6. The workmens cage of claim 5 wherein said pivotal arm has means for limiting its pivotal movement such that a pulling force on said second longitudinally inextensible means effects only a limited longitudinal displacement of said first longitudinally inextensible means which will releases the over-center hinge but will not have a pulling effect on the hinge after it is released.

7. The workmens cage of claim 1 wherein each of said top and side walls consist of a rigid framework covered with a screen material.

8. The workmens cage of claim 7 wherein said top wall has a removable door through which workmen can enter and leave the cage.

9. The workmens cage of claim 8 further including a ladder mounted upon said other side wall within the cage to allow workmen to climb into and out of the cage through the removable door.

10. The workmens cage of claim 4 further including quick release attachment means connecting said longitudinally inextensible means to the over-center hinge.

1 l. The workmen s cage of claim 7 wherein said rigid frameworks on the side walls include a plurality of substantially perpendicular frame members forming a grid of frame members on each side wall. 

1. A workmen''s cage for excavation work comprising combination: a top wall, a pair of side walls depending from opposite side edges of the top wall, pivot means connecting the top portion of one of said side walls to the top wall for pivotal movement of said one side wall selectively between a first position spaced from the other side wall and a second position wherein said one wall, below said pivot means, is pivoted inward convergent to said other wall, means fixing the angular relationship of said other side wall to the top wall, brace means extending between and interconnecting the side walls in downwardly spaced relation to said top wall, said brace means being selectively movable between an extended condition maintaining said one wall in the first position thereof and a collapsed condition whereby the brace means allows pivotal movement of said one side wall relative to the top wall, and release means connected to said brace means and operable from above said top wall for releasing said brace means from said extended condition and allowing pivotal movement of the lower portion of the one side wall toward the other while a fixed spacing is retained between the top edges of the side walls.
 2. The workmen''s cage of claim 1 wherein said one side wall is substantially perpendicular one the top wall when said brace means is in the bracing condition and is donwwardly convergent toward the other side wall when the brace means is in the collapsed condition.
 3. The workmen''s cage of claim 2 wherein said brace means consists of an over-center hinge which is released to its collapsed condition by a upwardly directed force.
 4. The workmen''s cage of claim 3 wherein said release means includes longitudinally inextensible means which can be pulled from a location above the cage to apply an upward pulling force to the over-center hinge to release the hinge to its collapsed condition.
 5. The workmen''s cage of claim 4 wherein said release means includes a pivotal arm mounted on the cage adjacent the top wall, said pivotal arm being connected by first longitudinally inextensible means to the over-center hinge and having second longitudinally inextensible means accessible from above the cage for releasing the hinge to its collapsed condition.
 6. The workmen''s cage of claim 5 wherein said pivotal arm has means for limiting its pivotal movement such that a pulling force on said second longitudinally inextensible means effects only a limited longitudinal displacement of said first longitudinally inextensible means which will releases the over-center hinge but will not have a pulling effect on the hinge after it is released.
 7. The workmen''s cage of claim 1 wherein each of said top and side walls consist of a rigid framework covered with a screen material.
 8. The workmen''s caGe of claim 7 wherein said top wall has a removable door through which workmen can enter and leave the cage.
 9. The workmen''s cage of claim 8 further including a ladder mounted upon said other side wall within the cage to allow workmen to climb into and out of the cage through the removable door.
 10. The workmen''s cage of claim 4 further including quick release attachment means connecting said longitudinally inextensible means to the over-center hinge.
 11. The workmen''s cage of claim 7 wherein said rigid frameworks on the side walls include a plurality of substantially perpendicular frame members forming a grid of frame members on each side wall. 